390results about "Polyphase network asymmetry reduction" patented technology

The invention relates to the technical field of power generation, power transformation or power distribution, and discloses a control method for preventing overload of an energy storage system transformer, which comprises the following steps: monitoring the three-phase total power and the power of each phase of a power grid side ammeter in real time, and calculating the three-phase unbalance degree based on the three-phase total power when the three-phase unbalance phenomenon occurs; when the three-phase unbalance degree is greater than a preset unbalance degree threshold value, dynamically adjusting the charging power of the energy storage converter according to a starting threshold value, a charging limiting threshold value and a charging forbidding threshold value by adopting a multi-threshold value dynamic adjustment mechanism; the phase with the maximum deviation between the power of each phase and the average power of the three phases is calculated as an overload phase, load reduction is performed on the overload phase based on a load increasing and decreasing strategy, load increasing is performed on a non-overload phase, and the adjusted three-phase power is obtained; a power distribution instruction is calculated in real time in combination with a dynamic response mechanism, and the three-phase unbalance degree does not exceed a safety threshold value in cooperation with total power control. The problems of easy overload, three-phase imbalance and slow response of a transformer in the prior art are solved, and the purposes of accurate load control, high system stability and high response speed are achieved.

The invention provides an impedance scanning device based on network side voltage dynamic compensation under a three-phase voltage imbalance working condition, and relates to the technical field of new energy station power electronic converter topology and control, the device comprises a three-phase rectifier, a direct current bus capacitor, an inverter, a voltage compensation device, a frequency sweeping device, a circuit breaker and a series transformer part, the three-phase rectifier is connected in series with inverters of the voltage compensation device and the frequency sweep device, a secondary side of a series transformer of the voltage compensation device is connected in series with a network side, a secondary side of a series transformer of the frequency sweep device is connected in series with a grid-connected point, and a primary side of the series transformer is connected to the inverters and is coupled to a secondary side of the series transformer; according to the device, the power grid side voltage is rectified through the voltage compensation unit and is compensated to the grid side after being subjected to single-stage inversion transformation, voltage compensation is achieved through the energy of a power grid when the voltage is unbalanced, and an external energy source or an interference source does not need to be introduced. After compensation, the accuracy of the frequency sweeping result is obviously improved.

The invention discloses a three-phase imbalance compensation method and system based on negative sequence current and a medium, and relates to the technical field related to power imbalance compensation, and the method comprises the steps: executing the three-phase current, voltage and reactive power data collection of a power distribution network, and carrying out the three-phase imbalance recognition through negative sequence current analysis; carrying out additional acquisition of a load mode and environment data on the power distribution network; taking the data acquisition result and the additional data set as input data to execute negative-sequence current change trend prediction; a double-layer compensation device is configured for cooperative control optimization; power distribution network balance compensation is executed through a time sequence compensation strategy, and time sequence window feedback is established; and carrying out adaptive strategy correction. The technical problems that in the prior art, a three-phase imbalance compensation strategy lacks perspectiveness and self-adaptive capacity and cannot cope with a dynamically-changing power grid scene, and consequently compensation precision and stability are poor are solved, and the technical effects that perspectiveness and predictive compensation is achieved, and three-phase imbalance compensation precision and stability are improved are achieved.

The invention discloses an intelligent commutation type three-phase imbalance dynamic treatment method for a power distribution network, relates to the technical field of power distribution network treatment, and aims to solve the problem of poor treatment effect of three-phase imbalance. By using the data mining and analysis technology, not only can the cost minimization path be calculated according to the current state, but also the future change can be pre-judged in combination with the load dynamic trend, so that the formulated switching strategy is more prospective and accurate, the generated high-dimensional mapping vector fuses the node characteristics and the neighbor node characteristics, and the switching efficiency is improved. By combining the use of a nonlinear activation function, the model can adaptively learn a load change rule, sensor equipment integrates various sensors and chips, has the functions of environment monitoring, power management and the like, and is matched with structural components to ensure the reliable operation of the device, reduce the operation and maintenance cost and difficulty and prolong the service life of the equipment.

The invention belongs to the technical field of electric energy quality control, and provides an energy storage type medium-voltage voltage sag and interruption treatment device and a control method thereof.The energy storage type medium-voltage voltage sag and interruption treatment device is arranged between a large power grid and a load in series and comprises a series converter PCS1, a parallel converter PCS2, an energy storage module, an injection type series transformer T1, a parallel transformer T2, a bypass static switch STS and a bypass relay KM1; wherein the injection type series transformer T1 is connected with a large power grid, and the parallel transformer T2 is connected with a load; the series converter PCS1 is connected with the injection type series transformer T1 through the bypass static switch STS and the bypass relay KM1, and compensation voltage is generated in real time through the injection type series transformer T1; the parallel converter PCS2 is respectively connected with the parallel transformer T2 and the common direct current busbar; and the energy storage module is arranged on the common direct current busbar between the series converter PCS1 and the parallel converter PCS2 in parallel.

The invention discloses a multi-line electric energy quality management and power flow transfer device and a control method, the device comprises a first regulation and control module, a second regulation and control module and a shared direct current bus, and the first regulation and control module and the second regulation and control module are of a vertically symmetrical structure; the two regulation and control modules are the same in structure, a primary winding of a three-winding transformer is connected with a medium-voltage alternating-current bus, a wire outlet end of a first secondary winding of the three-winding transformer is connected with a first load through a secondary winding of a first series transformer which is connected in series, and a primary winding of the first series transformer is connected with an alternating-current end of a first three-phase inverter; a wire outlet end of a second secondary winding of the three-winding transformer is connected with an alternating current end of the three-phase rectifier; the medium-voltage alternating-current bus is connected with a second load through a secondary winding of a second series transformer which is connected in series, and a primary winding of the second series transformer is connected with the alternating-current end of the second three-phase inverter. According to the invention, the increasingly complicated power quality requirements under multiple working conditions in the power distribution network facing multi-feeder decoupling regulation and control and mutual assistance are met.

The invention discloses a three-phase imbalance phase-change switch switching control system based on a graph neural network, and relates to the technical field of phase-change switch control. In order to solve the problems that in the prior art, deep analysis of load dynamic association and time sequence laws is lacked, so that a control strategy lags behind, switching actions are frequent, the treatment effect is limited, instruction time delay is large, the packet loss rate is high, and accurate synchronization of a commutation moment is difficult to guarantee. According to the method, the accuracy and efficiency of load characteristic analysis are greatly improved by constructing the load association graph structure and identifying the dynamic association mode, the graph neural network is utilized to extract the space-time sequence characteristics of the power grid topology and the load change, and the multi-dimensional and refined optimization of the commutation strategy is realized in combination with the multi-target optimization model, so that the method is suitable for large-scale popularization and application. The Mesh self-organizing network based on the power TD-LTE private network ensures that the instruction can be synchronized in millisecond and accurately sent to the phase-change switch, and provides a solid communication guarantee for effective execution of the strategy.

The invention belongs to the technical field of power grid control, and relates to a transformer area flexible interconnection system three-phase imbalance control method and device and a medium. Taking the transformer area converter controlled by the PQ control algorithm as a target transformer area converter; collecting a first control parameter output by an active power PI controller of the target transformer area converter; based on the upper and lower limits of the voltage target value of the DC bus, performing amplitude limiting setting on the first control parameter of the target transformer area converter to obtain the voltage target value; subtracting the voltage target value from the actual voltage value of the direct-current bus, inputting the difference value into the PI controller, and outputting a second control parameter of the target transformer area converter; taking the second control parameter as a direct-axis current target value, subtracting the direct-axis current target value from a direct-axis current actual value, and taking the difference value as the input of a direct-axis current PI controller; and controlling the target transformer area converter based on the voltage modulation signal output by the PQ control framework. The scheme can effectively improve the power supply reliability of the power distribution area and stabilize the DC bus voltage.

Disclosed in the present invention are an operation and maintenance method and apparatus for severe overload and three-phase imbalance of a distribution transformer, and a medium. The method comprises: by quantifying the degree of difference between devices as the distance between two points, performing clustering analysis on an operation and maintenance state of a distribution transformer, so as to obtain a classification result; and on the basis of a short-term single-phase severe overload category and a short-term three-phase severe overload category in the classification result, establishing a multi-objective optimization model and solving same, so as to obtain a multi-objective optimization result, and on this basis, formulating a day-ahead source-load distribution transformer operation and maintenance plan and performing operation and maintenance control on a distribution network. The present invention provides an operation and maintenance method and apparatus for severe overload and three-phase imbalance of a distribution transformer, and a medium. Solving a multi-objective optimization model to obtain a multi-objective optimization result can ensure that operational risks caused by three-phase imbalance are reduced while balancing three-phase loads, such that differentiated operation and maintenance can be achieved by means of a day-ahead source-load distribution transformer operation and maintenance plan, thereby solving the problem of difficulty in managing severe overload and three-phase imbalance of a distribution transformer to formulate a targeted operation and maintenance plan.

The invention relates to the technical field of power monitoring, in particular to a concentrator with an electrical equipment state monitoring function. Obtaining an unbalance degree according to the state characteristic values among the three phases; clustering is carried out according to the unbalance degree of all historical moments, and distribution intensity is obtained according to interval characteristics of different moments in a moment cluster; obtaining a data similarity according to the unbalance degree in the time cluster; obtaining reference credibility according to the moment quantity characteristics, the distribution intensity and the data similarity in the moment cluster; according to the difference characteristic of the unbalance degree corresponding to the current moment and the reference moment cluster and the reference credibility of the reference moment cluster, obtaining the abnormity degree; and obtaining an anomaly trend value according to the anomaly degree of the adjacent historical time period of the current moment. The early warning index of the current moment is obtained according to the abnormity degree and the abnormity trend value, and early warning is carried out, so that the monitoring accuracy of the concentrator on the power utilization state of the electrical equipment is improved.

The invention discloses an unbalanced load compensation method for a three-phase four-wire three-level converter. According to the method, a three-phase four-wire system three-level converter bridge arm voltage mathematical model is established based on sine carrier in-phase laminated modulation, and harmonic content analysis is completed; an SOGI-pro module is established (an error integration link is added at the input front end of a D axis of an SOGI filter, and D and Q axis second-order band-pass filters are transformed into third-order band-pass filters), so that the positive and negative sequence separation precision of three-phase unbalanced load voltage is improved. According to the method, the order of the SOGI filter is improved by reasonably designing a closed-loop transfer function, and the filtering effect of the SOGI filter in high and low frequency bands is enhanced. And a sequence-dividing imbalance compensation control loop is designed based on the three-sequence dq0 coordinate system, so that zero-static-error tracking of a positive-sequence fundamental component and powerful suppression of negative-sequence and zero-sequence imbalance components are realized. According to the invention, the accuracy of traditional positive and negative sequence separation is improved, so that the unbalanced load compensation effect under sequence separation control can be improved.

The invention discloses a three-phase unbalanced power flow line loss analysis method, which comprises the following steps of: establishing a power flow model of a three-phase unbalanced system based on a sequence component method; the power flow model comprises admittance matrixes respectively corresponding to a positive sequence, a negative sequence and a zero sequence, and equivalent admittance corresponding to any two of the positive sequence, the negative sequence and the zero sequence; converting the power flow model, and determining a first relational expression among the coupled positive sequence current, the equivalent admittance and the uncoupled positive sequence current, and a second relational expression among the coupled negative sequence current, the equivalent admittance and the uncoupled negative sequence current; determining a positive sequence electrical component according to the first relational expression, and determining a negative sequence electrical component according to the second relational expression; and determining the line loss of the three-phase unbalanced system according to the positive sequence electrical component and the negative sequence electrical component. According to the method provided by the invention, the accuracy of line loss analysis can be improved.

Disclosed embodiments provide methods, systems, and computer program products for implementing enhanced phase power load balancing of a set of systems (e.g., the set of systems of a data center) using a subset of the systems. Disclosed embodiments extract phase currents of a three-phase power source of the set of systems, and determine, based on extracted phase currents for the set of systems, input phase power load balancing for the subset of the systems. Disclosed embodiments alter the current input phase power balancing of the subset, unbalancing the input phase power load for the subset of the systems to provide enhanced phase power load balancing of the set of systems. Altering the current input phase power balancing for the subset of the systems can be implemented by power shifting between power supply units (PSUs), phase rotations, or input phase switching of power distribution unit (PDU) switchable output ports.

The invention discloses an active and reactive comprehensive oscillation quantity minimization cooperative control method under a current constraint condition, and the method comprises the steps: analyzing an inverter side current converter in a power grid voltage imbalance state, and quantifying the frequency doubling fluctuation quantity of active power and reactive power caused by a negative sequence component; a third harmonic voltage compensation method is adopted to suppress negative sequence current, the third harmonic voltage compensation amount of the converter is dynamically adjusted, and three-phase current balance is regulated and controlled; on the basis of active and reactive power fluctuation suppression of a negative-sequence current compensation method, an optimization function with the purpose of minimizing the comprehensive fluctuation quantity of active power and reactive power is constructed by utilizing controllable negative-sequence current compensation quantity and eliminating frequency doubling fluctuation quantity of active power and reactive power, and an optimal negative-sequence current compensation scheme is solved in real time by adopting a particle swarm optimization algorithm. Cooperative suppression of three-phase current balance and power oscillation is achieved, and the operation stability and the power transmission capacity of the inverter side converter under an asymmetric fault are remarkably improved under the current amplitude limiting condition.

The invention discloses a method and a system for regulating and controlling imbalance of a power distribution area, which are used for solving the technical problem of poor operation stability of the power distribution area caused by a traditional method for regulating and controlling imbalance of the power distribution area. The method comprises the following steps: acquiring three-phase bus voltage and three-phase current of a power distribution area; generating a power distribution area three-phase component voltage and a power distribution area power optimization objective function according to the power distribution area three-phase bus voltage and the power distribution area three-phase current; solving the power optimization objective function of the power distribution area, and outputting predicted power of the power distribution area; calculating a three-phase reference current of the power distribution area based on the predicted power of the power distribution area and the three-phase component voltage of the power distribution area; and according to the three-phase reference current of the power distribution area, generating a power distribution area imbalance regulation and control signal.

The invention relates to a power system voltage control technology, in particular to a method and equipment for maintaining grid-connected point voltage three-phase balance under weak power grid unbalanced disturbance, and the method comprises the following steps: firstly, establishing a small signal model of a converter grid-connected system after unbalanced disturbance, and emphatically considering the phasing error influence of a phase-locked loop transient process; then, the fluctuation quantity of the amplitude and phase of the PCC voltage induced by unbalanced disturbance is accurately calculated, the influence is counteracted through a power outer ring feed-forward compensation mode, and three-phase balance of the PCC voltage in the transient state and the steady state process is achieved under the condition that the weak power grid unbalanced disturbance is maintained. According to the method, the influence of the machine-network interaction of the weak power grid on the dynamic characteristics of the PCC voltage is considered, and a better voltage balance maintaining effect is achieved in the weak power grid. Through composite control, according to PCC voltage vector amplitude and phase disturbance compensation, system transient state and steady state whole-process voltage balance maintenance after unbalanced disturbance is realized. The control structure is simple, and the robustness of the system is improved.

The invention discloses a transformer parallel operation circulating current suppression method and system based on a cloud edge collaborative architecture, and relates to the technical field of power grid control, and the method comprises the steps: an edge node collects the multi-source dynamic data of a parallel transformer in real time, and constructs a local dynamic impedance model of a single transformer; the cloud receives the multi-modal data uploaded by each edge node, inputs the multi-modal data into an LSTM-SVM hybrid model trained based on a historical database, generates an impedance prediction weight of each edge node, and issues the impedance prediction weight to the corresponding edge node; the edge node receives the impedance prediction weight and injects the impedance prediction weight into a local dynamic impedance model to generate a corrected dynamic impedance matrix; and calculating a circulating current suppression instruction according to the corrected dynamic impedance matrix, and executing real-time regulation and control based on the circulating current suppression instruction. According to the method, the impedance prediction weight is generated through real-time collection of the edge nodes and calculation of the cloud, the local dynamic impedance model is effectively corrected, and then the circulating current suppression instruction is accurately calculated.

The invention relates to the technical field of intelligent operation of a power distribution network, in particular to an intelligent three-phase imbalance treatment method, which comprises the following steps of: firstly, acquiring three-phase current, three-phase voltage and electrical characteristic quantity of each single-phase load, and carrying out commutation adaptability evaluation on the load based on a real-time power factor, a current harmonic distortion rate and a load power flow direction; and calculating the three-phase unbalance degree of each power supply branch, identifying an extreme branch with the unbalance degree exceeding the standard, and screening out loads with optimal commutation adaptability parameters to form a candidate load set. And generating a commutation priority sequence for the candidate load through a historical commutation frequency and real-time contribution degree two-factor model. And triggering zero-millisecond seamless commutation under the conditions of meeting a safe voltage threshold and equal voltage time, verifying a switching result after commutation, limiting the number of commutation times of single treatment, and monitoring the three-phase unbalance degree in real time until the three-phase unbalance degree is recovered to a qualified range. According to the invention, the accuracy and safety of the commutation decision can be improved, and the dynamic balance adjustment of the three-phase load is realized.

The invention provides a three-phase balance user phase adjustment method based on multi-objective optimization control, and relates to the technical field of power system control. According to the technical scheme provided by the invention, after the phase distribution results under different constraint conditions are calculated, the problem of deterioration of other indexes possibly caused by single target optimization can be avoided by constructing the multi-objective function containing the indexes. And meanwhile, multi-objective function value calculation and comparison are carried out on each phase distribution scheme, and the phase distribution scheme with the minimum multi-objective function value is selected as the optimal scheme, so that the overall optimality and the balance of each technical index can be considered. Compared with a phase adjustment mode in which only a single-phase meter or a three-phase meter is considered in the prior art, the phase adjustment scheme provided by the invention adopts a multi-objective function to realize trade-off optimization among indexes for the condition that the single-phase meter and the three-phase meter exist at the same time, so that accurate phase adjustment can be realized, and the load balancing effect is improved.

The invention relates to the technical field of power supply and distribution, in particular to a three-phase load intelligent regulation and control method based on ammeter data, and the method comprises the steps: carrying out the empirical mode decomposition of each phase of current time sequence in three-phase current time sequence data, and obtaining a plurality of internal mode function components; performing fast Fourier transform on each internal mode function component to obtain frequency domain information, calculating power spectrum density and extracting a peak value to obtain a characteristic period set; setting a basic prior period, generating a prior period set based on different multiples, calculating the matching confidence of each characteristic period in each internal modal function component and each prior period in the prior period set, and constructing a corresponding normalized characteristic period matrix; constructing a global period confidence coefficient vector; and the global period confidence vector is used as the input of the long short-term memory network, and the change trend of the target signal is predicted, so that the prediction precision of the LSTM model on the load change is improved, and intelligent regulation and control of the three-phase load are realized.

The invention provides an electric energy quality control method and system based on an energy storage system, relates to the technical field of electric energy quality control, and aims to identify collaborative disturbance attributes during voltage sag and three-phase imbalance through dynamic distortion information, perform scheduling amplitude limiting compensation on the collaborative disturbance attributes, and improve the control accuracy of the electric energy quality. Obtaining a layered amplitude limiting inflection point when the electric energy in the energy storage system is intelligently scheduled in the load-storage balance constraint region; carrying out fusion correction on the circulation out-of-limit deviation, generating a dynamic peak regulation criterion when the power grid carries out energy storage transfer adjustment in multiple time scales, and further determining a regulation and control guidance strategy during electric energy balance regulation and control in the energy storage system according to the dynamic peak regulation criterion; and performing tolerance adaptation control on the power quality of the power distribution network in the composite disturbance scene according to the hierarchical amplitude limiting inflection point and the regulation and control guidance strategy. According to the invention, tolerance adaptation control can be carried out on the power quality of the power distribution network in a composite disturbance scene, so that the power quality management and control efficiency under the participation of an energy storage system is improved.

The invention discloses an unbalance compensation method and system for an energy storage converter, and belongs to the field of power electronics and electric energy quality treatment. The system comprises a power instruction analysis module, a current reference generation module, a negative sequence current control loop module, a zero sequence control loop module, a positive sequence control loop module, a pulse width modulation module, a first conversion module and a second conversion module, the current reference generation module is respectively connected with the negative sequence current control loop module and the positive sequence control loop module; the third end and the fourth end of the negative sequence current control loop module are connected with the pulse width modulation module through the second conversion module; the third end and the fourth end of the zero sequence control loop module and the third end and the fourth end of the positive sequence control loop module are connected with the pulse width modulation module through the first conversion module. According to the method, the energy storage and compensation functions of the PCS can be seamlessly integrated under a unified control framework, so that the control system is greatly simplified, and the performance is remarkably improved.

The invention provides a dynamic three-phase imbalance treatment system and method with an intelligent phase-change switch, and relates to the technical field of power system distribution network operation control. The system comprises a load monitoring unit, a central control unit and an intelligent phase-change switch array. According to the treatment method, the load monitoring unit collects load current and voltage data of each phase in real time and transmits the data to the central control unit; the central control unit adopts a load balance decision model based on an improved particle swarm algorithm to analyze and process the acquired data so as to calculate an optimal commutation scheme; and the intelligent phase-change switch array completes load phase sequence switching within millisecond-level time through a solid-state phase-change switch with rapid on-off capability according to the control instruction, so that three-phase load dynamic balance adjustment is realized. By adopting the scheme of the invention, the real-time performance and the adjustment precision of three-phase imbalance treatment can be obviously improved, the method adapts to complex and changeable distribution network load working conditions, the line loss is effectively reduced, and the utilization rate of the transformer and the operation stability of the distribution network are improved.

The invention provides a power network three-phase balance optimization method based on a multi-target particle swarm optimization algorithm, which belongs to the technical field of power grid three-phase balance adjustment, and comprises the following steps: acquiring low-voltage transformer area network topology and user power consumption data, initializing a particle swarm population, updating particle positions through a dynamic inertia weight and a self-adaptive learning factor, and optimizing the power grid three-phase balance. The three-phase unbalance degree, the voltage deviation and the economic cost are evaluated in combination with low-voltage power flow calculation, an external archiving mechanism, a crowding distance strategy and variation maintenance solution set diversity are adopted, an optimal phase sequence adjustment scheme and wire diameter configuration are output, and aiming at the characteristics of high impedance and three-phase load imbalance of a low-voltage transformer area, the voltage quality is remarkably improved, and the power consumption is reduced. The method is suitable for intelligent reconstruction of low-voltage distribution networks in residential areas, small industrial and commercial areas and the like, and has good practicability and economical efficiency.

The utility model provides an electric energy quality control system, and belongs to the technical field of power electronics. The electric energy quality control system comprises a transformer module, a power conversion module and a switch module, and the power conversion module comprises an off-grid inverter; one end of the transformer module is used for accessing a three-phase power grid, and the other end of the transformer module is connected with an alternating current port of an off-grid inverter in the power conversion module and a zero line; the alternating current port of the off-grid inverter is also connected with the input end of the switch module, the output end of the switch module is connected with the zero line of the off-grid inverter, and the control end of the switch module is respectively connected with the signal control end of the off-grid inverter and an external driving circuit. According to the invention, the stability and reliability of the power quality control system can be improved.

A kind of multi-line power quality treatment and power flow transfer device and control method, the device includes first regulating module, second regulating module and shared DC bus, first regulating module and second regulating module present upper and lower symmetrical structure;Two regulating module structures are same, and all are three-winding transformer primary winding and medium voltage AC bus connection, the first secondary winding of three-winding transformer is connected with first load through the secondary winding of first series transformer connected in series, the primary winding of first series transformer is connected with the AC end of first three-phase inverter;The AC end of three-phase rectifier is connected with the secondary winding of three-winding transformer;Medium voltage AC bus is connected with second load through the secondary winding of second series transformer connected in series, the primary winding of second series transformer is connected with the AC end of second three-phase inverter.The present application solves the increasingly complex power quality demand of decoupling regulation and mutual aid, multi-working condition in distribution network facing multi-feed line.

The present invention relates to a method for establishing an optimal power flow model of a three-phase unbalanced distribution network, and belongs to the technical field of power flow optimization of a three-phase unbalanced distribution network. With the large-scale access of electric vehicles and photovoltaic power generation systems to the power grid, the single-phase power supply within the distribution network has increased, the load has increased, and the severity of its single-phase operation problem has been aggravated. In order to ensure the power supply quality of the power grid, a large number of adjustable single- and three-phase compensation and regulation equipment have been used in the power grid. Taking into account the above power grid operation conditions, the present invention first establishes a multi-period distribution network optimal power flow model containing reactive compensation devices and energy storage; through second-order cone programming, the original non-convex nonlinear optimal power flow model is transformed into a linear model, which reduces the difficulty of solving without losing accuracy and improves the solution efficiency. It provides a good reference for subsequent research on the three-phase imbalance problem in the optimal power flow process of the distribution network.

The invention relates to a method for identifying asymmetrical vibrations during the operation of an electric device (1) which is connected to a high-voltage grid, wherein - vibrations of the electric device (1) are detected using vibration sensors (8) which provide measured values on the output side, - the measured values and / or values derived from the measured values are transmitted to a communication unit (12) via a close-range communication connection (11), - the measured values and / or the values derived from the measured values are transmitted by the communication unit (12) to a data processing cloud (9) via a far-range communication connection (13), - the measured values and / or the values derived from the measured values are separated into frequency components by the data processing cloud (9) using a Fourier transformation, thereby obtaining a frequency spectrum, - odd and even frequency components of the frequency spectrum are ascertained on the basis of a base frequency of the high-voltage supply grid and put into a ratio R relative to one another, and - the presence of asymmetrical vibrations is indicated if the ratio R exceeds a specified threshold.

To provide an automatic voltage balancing device and an automatic voltage balancing method that can improve a three-phase unbalanced voltage in a distribution line.SOLUTION: An automatic voltage balancing device is composed of a transformer portion and a control portion. The transformer portion connects a tap changer composed of a mechanical diverter switch and a tap selector in series with a distribution line, and the tap changer changes the tap while the transformer portion is being operated. When a substation is connected to a primary side, the control portion calculates an average value of a primary voltage of the tap changer, and controls the voltage such that a secondary voltage of each phase approaches the average value. When the substation is connected to a secondary side, the control portion calculates an average value of a secondary voltage of the tap changer, and controls the voltage such that the primary voltage of each phase approaches the average value.SELECTED DRAWING: Figure 1

The application discloses a kind of three-phase load imbalance monitoring alarm method.The method comprises: obtaining the current data, power data and appeal work order data of target area at multiple sampling time points;According to the current data and power data, determine the three-phase load imbalance type of target area;According to three-phase load imbalance type and appeal work order data, determine whether to send risk alarm to target area.The technical scheme provided by the embodiment of the application obtains the current data and power data of multiple sampling time points in the target area, thereby obtaining the working condition of the distribution transformer in the target area at multiple sampling time points, and then determining the three-phase load imbalance type of the target area.Combined with the appeal work order data fed back by the actual experience of users in the target area, the power supply condition in the target area can be judged more accurately, and the target area needing to send risk alarm is prompted, so that the technical effect of improving the management efficiency of power grid and the satisfaction of users is realized.